This invention relates to a diaphragm pump, particularly for the generation of vacuum, in which the central portion of the diaphragm is attached to a connecting rod of a crank drive, whereas its periphery is fixed in the pump chamber or some other part of the crank case of the pump.
Diaphragm pumps of the aforementioned kind are known in the art. A difficulty which arises in such diaphragm pumps is that of reducing or completely eliminating any clearance between the diaphragm and the surface of a wall facing the diaphragm and forming with the latter a pumping chamber at the top dead-center position of the crank drive. Any such remaining clearance will prevent the generation of a high vacuum and thereby reduce the performance of such a diaphragm pump.
Also known in the art are diaphragm pumps comprising a plurality of pumping elements working in series and disposed about a common drive shaft. However, the attainable vacuum cannot thus be substantially improved, despite a considerable increase in cost.